144 lines
4.3 KiB
C++
144 lines
4.3 KiB
C++
// Copyright 2016 Citra Emulator Project
|
|
// Licensed under GPLv2 or any later version
|
|
// Refer to the license.txt file included.
|
|
|
|
#include <chrono>
|
|
#include <cmath>
|
|
#include <vector>
|
|
#include <SoundTouch.h>
|
|
#include "audio_core/audio_core.h"
|
|
#include "audio_core/time_stretch.h"
|
|
#include "common/common_types.h"
|
|
#include "common/logging/log.h"
|
|
#include "common/math_util.h"
|
|
|
|
using steady_clock = std::chrono::steady_clock;
|
|
|
|
namespace AudioCore {
|
|
|
|
constexpr double MIN_RATIO = 0.1;
|
|
constexpr double MAX_RATIO = 100.0;
|
|
|
|
static double ClampRatio(double ratio) {
|
|
return MathUtil::Clamp(ratio, MIN_RATIO, MAX_RATIO);
|
|
}
|
|
|
|
constexpr double MIN_DELAY_TIME = 0.05; // Units: seconds
|
|
constexpr double MAX_DELAY_TIME = 0.25; // Units: seconds
|
|
constexpr size_t DROP_FRAMES_SAMPLE_DELAY = 16000; // Units: samples
|
|
|
|
constexpr double SMOOTHING_FACTOR = 0.007;
|
|
|
|
struct TimeStretcher::Impl {
|
|
soundtouch::SoundTouch soundtouch;
|
|
|
|
steady_clock::time_point frame_timer = steady_clock::now();
|
|
size_t samples_queued = 0;
|
|
|
|
double smoothed_ratio = 1.0;
|
|
|
|
double sample_rate = static_cast<double>(native_sample_rate);
|
|
};
|
|
|
|
std::vector<s16> TimeStretcher::Process(size_t samples_in_queue) {
|
|
// This is a very simple algorithm without any fancy control theory. It works and is stable.
|
|
|
|
double ratio = CalculateCurrentRatio();
|
|
ratio = CorrectForUnderAndOverflow(ratio, samples_in_queue);
|
|
impl->smoothed_ratio =
|
|
(1.0 - SMOOTHING_FACTOR) * impl->smoothed_ratio + SMOOTHING_FACTOR * ratio;
|
|
impl->smoothed_ratio = ClampRatio(impl->smoothed_ratio);
|
|
|
|
// SoundTouch's tempo definition the inverse of our ratio definition.
|
|
impl->soundtouch.setTempo(1.0 / impl->smoothed_ratio);
|
|
|
|
std::vector<s16> samples = GetSamples();
|
|
if (samples_in_queue >= DROP_FRAMES_SAMPLE_DELAY) {
|
|
samples.clear();
|
|
LOG_DEBUG(Audio, "Dropping frames!");
|
|
}
|
|
return samples;
|
|
}
|
|
|
|
TimeStretcher::TimeStretcher() : impl(std::make_unique<Impl>()) {
|
|
impl->soundtouch.setPitch(1.0);
|
|
impl->soundtouch.setChannels(2);
|
|
impl->soundtouch.setSampleRate(native_sample_rate);
|
|
Reset();
|
|
}
|
|
|
|
TimeStretcher::~TimeStretcher() {
|
|
impl->soundtouch.clear();
|
|
}
|
|
|
|
void TimeStretcher::SetOutputSampleRate(unsigned int sample_rate) {
|
|
impl->sample_rate = static_cast<double>(sample_rate);
|
|
impl->soundtouch.setRate(static_cast<double>(native_sample_rate) / impl->sample_rate);
|
|
}
|
|
|
|
void TimeStretcher::AddSamples(const s16* buffer, size_t num_samples) {
|
|
impl->soundtouch.putSamples(buffer, static_cast<uint>(num_samples));
|
|
impl->samples_queued += num_samples;
|
|
}
|
|
|
|
void TimeStretcher::Flush() {
|
|
impl->soundtouch.flush();
|
|
}
|
|
|
|
void TimeStretcher::Reset() {
|
|
impl->soundtouch.setTempo(1.0);
|
|
impl->soundtouch.clear();
|
|
impl->smoothed_ratio = 1.0;
|
|
impl->frame_timer = steady_clock::now();
|
|
impl->samples_queued = 0;
|
|
SetOutputSampleRate(native_sample_rate);
|
|
}
|
|
|
|
double TimeStretcher::CalculateCurrentRatio() {
|
|
const steady_clock::time_point now = steady_clock::now();
|
|
const std::chrono::duration<double> duration = now - impl->frame_timer;
|
|
|
|
const double expected_time =
|
|
static_cast<double>(impl->samples_queued) / static_cast<double>(native_sample_rate);
|
|
const double actual_time = duration.count();
|
|
|
|
double ratio;
|
|
if (expected_time != 0) {
|
|
ratio = ClampRatio(actual_time / expected_time);
|
|
} else {
|
|
ratio = impl->smoothed_ratio;
|
|
}
|
|
|
|
impl->frame_timer = now;
|
|
impl->samples_queued = 0;
|
|
|
|
return ratio;
|
|
}
|
|
|
|
double TimeStretcher::CorrectForUnderAndOverflow(double ratio, size_t sample_delay) const {
|
|
const size_t min_sample_delay = static_cast<size_t>(MIN_DELAY_TIME * impl->sample_rate);
|
|
const size_t max_sample_delay = static_cast<size_t>(MAX_DELAY_TIME * impl->sample_rate);
|
|
|
|
if (sample_delay < min_sample_delay) {
|
|
// Make the ratio bigger.
|
|
ratio = ratio > 1.0 ? ratio * ratio : sqrt(ratio);
|
|
} else if (sample_delay > max_sample_delay) {
|
|
// Make the ratio smaller.
|
|
ratio = ratio > 1.0 ? sqrt(ratio) : ratio * ratio;
|
|
}
|
|
|
|
return ClampRatio(ratio);
|
|
}
|
|
|
|
std::vector<s16> TimeStretcher::GetSamples() {
|
|
uint available = impl->soundtouch.numSamples();
|
|
|
|
std::vector<s16> output(static_cast<size_t>(available) * 2);
|
|
|
|
impl->soundtouch.receiveSamples(output.data(), available);
|
|
|
|
return output;
|
|
}
|
|
|
|
} // namespace AudioCore
|